TORONTO — Does Hailee Steinfeld know how good she is?

It’s a question writer-director Kelly Fremon Craig and producer James L. Brooks would ask themselves after watching the young actress shoot a take while making their high-school comedy “The Edge of Seventeen.”

“Jim and I would sit there and go, ‘Holy god!'” says Craig. “And after we’d call cut, Jim and I would be staring at each other with our mouths open and she’d just be on her phone like she didn’t even know she did something that great.”

Steinfeld, an Oscar nominee at 14, is having another breakthrough at 19. In Craig’s much-lauded directorial debut “The Edge of Seventeen,” the young star of the Coen brothers’ “True Grit” proves that she’s matured into one of the finest (and funniest) actresses of her generation.

It’s a comic and heartfelt coming-of-age movie in which Steinfeld stars as Nadine, a Job-like high-school junior who resents her fellow high-schoolers as “mouth breathers”; she’s equal parts narcissistic and self-loathing, and altogether witty, honest and original.

“This character is so much like myself,” she said.

Steinfeld was making a brief stop at the Toronto International Film Festival, where “The Edge of Seventeen” was the closing film. It was brief because in between acting, Steinfeld is trying to become a pop star; she was in between concert stops, opening for Meghan Trainor.

Steinfeld put out her first EP, “Haiz,” last November. Her single “Starving” got up to 14 on Billboard.

“When you stand on that stage, it’s you,” she said. “It’s me going out there and being vulnerable in front of a bunch of people and having fun.”

– From news service reports